Tell processors when forms have been submitted in Welsh

[thomasiles]

Add language to submission email, json, and CSV

Important

I've added some commits to this since it was reviewed to make the 'language' field in CSV and JSON submissions only show when the form has a welsh version.

Trello card: https://trello.com/c/uTDx5owN/2761-needed-before-launch-update-form-submission-templates-for-welsh-forms

This PR adds:

• a message to submission emails when fillers have completed a form in Welsh
• a "Language" field in CSVs which is either 'en' or 'cy'
• a "Language" attribute to JSON submissions with a value of either 'en' or 'cy'

The Language fields in the CSV and JSON appear for every submission, English and Welsh. The message in the submission email only shows in Welsh submissions.

To decide if a submission was in Welsh, we check if any questions have been answered in the Welsh locale. This is a simple test which captures how many teams deal with Welsh submissions in their current services. It will probably be refined as we learn more about how processors work with Welsh forms.

Changing session and submission code can break fillers half-way through a session. I've tried to avoid this by making the session code and submission_locale methods work even when they don't have any values set. I've also tested email and s3 submissions in dev to make sure nothing has broken.

The JSON schema kept in the product pages needs to be updated when this is released. I'll create a PR when this one has passed review to update it.

How it looks in the Email

The CSV

The JSON

{
  "$schema": "https://dev.forms.service.gov.uk/json-submissions/v1/schema",
  "form_name": "a test welsh form",
  "submission_reference": "CV3KS2C3",
  "submitted_at": "2026-01-22T17:01:10.625Z",
  "language": "cy",
  "answers": [
    {
      "question_id": "MgMQgZtq",
      "question_text": "What's the highest number you can count to?",
      "answer_text": "123"
    },
    {
      "question_id": "ehEDgsgq",
      "question_text": "Whats the next number after that?",
      "answer_text": "234"
    }
  ]
}

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[DavidBiddle]

Really nice and readable PR, and well broken up 🎉

All works for me when testing locally - if at least one answer is entered on a Welsh screen, the email contains the line about Welsh and the JSON/CSV include the welshlanguage flag.

[DavidBiddle]

Code looks good 🎉

I've tested locally and can see what I think is the correct behaviour:

• monolingual form:
  • no message in the email text
  • no language field in the JSON or CSV
• bilingual form answered entirely on the English routes:
  • no message in the email text
  • language set to en in the JSON and CSV
• bilingual form answered partly on the Welsh routes:
  • message in the email text
  • language set to cy in the JSON and CSV

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
9.4% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

🎉 A review copy of this PR has been deployed! It is made of up two components

1. A review copy of forms-runner
2. A production copy of forms-admin

Important

Not all of the functionality of forms-runner is present in review apps.
Functionality such as sending emails, file upload, and S3 submission types are
deliberately disabled for the sake of simplifying review apps.

You should use the full dev environment to test the functionality which is disabled here.

It may take 5 minutes or so for the application to be fully deployed and working. If it still isn't ready
after 5 minutes, there may be something wrong with the ECS task. You will need to go to the integration AWS account
to debug, or otherwise ask an infrastructure person.

For the sign in details and more information, see the review apps wiki page.